1. Field of the Invention
The present invention relates to an antenna apparatus for a mobile communication terminal such as a Personal Communication Service (PCS) terminal, a cellular phone and so forth, and more particularly to an antenna apparatus capable of receiving a Digital Media Broadcasting (DMB) signal as well as a phone call signal for general voice transmission/reception.
2. Description of the Related Art
Mobile communication terminals have recently become popular, and with their popularity, a desire to develop complex mobile communication terminals to which, aside from a simple phone call function, various functions for satisfying consumers' needs are added has arisen. Other than the existing voice phone call, additional services desired by users include, for example, a Video On Demand (VOD) function, a video calling function, a digital camera function, an Internet browsing function, a digital broadcasting viewing function and the like.
Of the various additional services stated above, the digital broadcasting service may be divided into a satellite digital broadcasting service and a terrestrial digital broadcasting service. The satellite digital broadcasting service mainly aims at a mobile-type service, and enables users to view multi-channel broadcasting anytime and anywhere through portable receivers (e.g., cellular phones, PCS terminals, etc.) or vehicle receivers capable of receiving satellite signals.
The concept of the terrestrial digital broadcasting, which is similar to Digital Audio Broadcasting (DAB), uses an unassigned channel, such as Very High Frequency (VHF) channel no. 12, for broadcasting multimedia for reception by mobile communication terminals. The terrestrial digital broadcasting service refers to a service in which television broadcasting, radio broadcasting and data broadcasting can be transmitted and/or received using a multi-channel.
At present, with the advancement of digital broadcasting and mobile communication technologies, a digital broadcasting service for enabling users to view digital broadcasting while moving such as a DMB service using a mobile communication network, is being developed.
A mobile communication terminal, which has a function for receiving DMB signals using a mobile communication network, not only has a mobile phone function, but can also display DMB programs by means of the mobile communication terminal's display device. Such a mobile communication terminal having the DMB function includes at least two radio signal processing units because a frequency band required for its inherent voice and data transmission/reception functions is different from a DMB frequency band, and thus has a phone mode, a standby mode and a DMB mode serving as both the standby mode and a video receiving mode. In mobile communication terminals, it is common that an antenna for DMB signal reception is connected to an internal tuner and an antenna for voice signal transmission/reception is connected to a duplexer.
However, since the mobile communication terminal having the DMB function must receive DMB signals as well as signals for general voice transmission/reception, it has two antenna apparatuses for receiving the two types of signals, respectively and other components related to the two antenna apparatuses, and thus its structure becomes more complicated than that of a ordinary mobile communication terminal having only a voice phone call function. In other words, the two antenna apparatuses, that is, an antenna apparatus for receiving DMB signals and a communication antenna apparatus are separately mounted to a single body of the mobile communication terminal, which makes the miniaturization of the body of the mobile communication terminal more difficult.
Moreover, due to the fact that the DMB antenna apparatus and the communication antenna apparatus are mounted to a single body of the mobile communication terminal, the mobile communication device may not be as portable as a mobile communication terminal having a single antenna. This is because both the DMB antenna apparatus and the communication antenna apparatus are constructed as retractable antenna apparatuses, and thus the respective antenna apparatuses protrude from the body of the mobile communication terminal. Here, the retractable antenna apparatus refers to an antenna apparatus such as a well-known whip or rod antenna.